Following the shock resignation of Isobel Redmond from the leadership position at the party's regional planning conference in Port Pirie yesterday, remaining members of the party have been scrambling to find candidates for the vacated role.

Mr Marshall was the first to express his will to run in the leadership ballot at a press conference he hosted outside of the Liberal Party conference in Port Pirie this morning.

Marshall told the waiting media he had received overwhelming support from his party colleague overnight when he expressed interest in running for the position and said he was unaware of any other challengers.

"There have been issues in terms of party unity in the past, we have to put that behind us, we have a hopeless government in South Australia, they've got to be held to account and what I bring is an approach to bring everybody together, focussed around our objective."

Mr Marshall said he would not be running on a party ticket, nominating for the leadership position without an accompanying nominee for the deputy leadership role.

Marshall has been the sitting member for Norwood since 2010, and remained relatively unscathed in the party's previous leadership stoushes between now former leaders Martin Hamilton-Smith and Isobel Redmond.

With rumoured challenger Alexander Downer expressing no firm current wishes to enter state politics and challenge for the position, it is possible that Marshall may enter the leadership ballot unopposed.

Vicki Chapman has announced she will run for the deputy leader position, with Martin Hamilton-Smith also saying he is considering contesting the deputy role.

The ballot for the SA Liberal Party leadership positions will be held Monday morning at 9:00am.